The primary objective of this study is to determine the concentration - response relationship of intravenous BG9719 alone and in association with furosemide in subjects with moderate to severe congestive heart failure and mild to moderate renal failure. Secondary objectives are to determine whether BG9719 alone or in association with furosemide maintain renal function in comparison to furosemide or placebo alone: to determine whether BD9719 alone or in association with furosomide causes less potassium loss than furosemide alone; to determine the difference in sodium excretion concentration-response curves between the association of furosemide and BF9719 relative to BG9719 alone; to assess the evidence of clinical benefit with treatment with BG9719 using global assessment scales, edema score, dyspnea scales, and weight loss; and to determine the tolerability of continuous infusion with BG9719 alone and in association with furosemide."